In some cases, it is relevant to represent the organizational structure independently of the people within that structure; for example, it is relevant to represent the position of the Member of Parliament for Avalon even when no one holds that position. A post is such a position that exists independently of the person holding it.

A post should not be confused with a role, which describes a function that a person can fulfill. For example, many people fulfill the role of “CEO” in different organizations, but only one person holds the post of “CEO at Apple Inc.” Indeed, the post of the MP for Avalon could be described as having the role of MP.

According to this data specification, a person holds a post in an organization through their membership in that organization, as illustrated by the class diagram below.

2.1. Changes to data model

Michael Ignatieff was Member of Parliament for Etobicoke—Lakeshore until 2011.

the date on which the person currently holding a post started holding it

Barack Obama assumed office January 20, 2009.

Within the Organization ontology, there is also significant overlap in responsibility between the Membership and Post classes, leading to confusion as to when one, the other, or both is required or recommended for a particular use case.

According to the Organization ontology, people hold posts directly; in order to resolve the above issues, in this data specification, people hold posts indirectly through memberships. Therefore, the properties org:heldBy and org:holdsshould not be used.

2.2. Range restrictions

According to the Organization ontology, either a person or an organization can hold a post in an organization; in this data specification, only a person can hold a post in an organization.

1. The role property appears on both the Post and Membership classes, as there are uses cases where you will have no posts (e.g. describing club membership) and others where you will have no memberships (e.g. describing organizational structure).